Help with 1.7 litre diesel not reaching full RPM

[Dencope]

Hey guys,

Hoping someone may have a few suggestions on where to start troubleshooting an issue on a 1.7 litre diesel cummings made by isuzu in a 2008 Campion. It is a friends boat and he has sunk a lot of money trying to rectify this issue to no avail. I'm going to have a look at it tomorrow and do have some experience with diesels but not an expert. Basically the way he describes it is it runs fine at idle and up to 2200 RPM but will not go any higher, it previously ran upwards 4200 RPM.

So far he has checked the mechanical linkage, fuel supply (filters etc.) and had the fuel pump rebuilt to the tune of $2,000.
He says no black smoke when trying to apply throttle.

Anyways, if anyone has any info or tips on where to start troubleshooting this problem it would be much appreciated. Thanks in advance for any advice!

 

[trophy fisher]

Is the turbo seized? If it's not making any boost it will not make any power and fuel would be cut due to lack of boost pressure. TF

 

[Sir Reel]

Bled all the fuel lines?

Here is a good little trouble shooting guide.

http://www.sbmar.com/Maintenance/PDF/Low-Power-Troubleshooting.pdf

and this one

http://www.sbmar.com/articles/understanding_low_power_troubleshooting/

 

[Fishin'Zinn]

Water in fuel tank? Probably checked already... Although I would use a portable fuel tank with some fresh diesel in it and see if it worked differently to isolate that as a non-issue

 

[noluck]

will it pull rpm out of gear?

 

[Dencope]

Water in fuel tank? Probably checked already... Although I would use a portable fuel tank with some fresh diesel in it and see if it worked differently to isolate that as a non-issue

Yeah he tried with suction straight to a clean jar of diesel bypassing everything. Thanks all this info and ideas is great!

 

[Dencope]

will it pull rpm out of gear?

I don't think so but I'll check that today when I'm there to confirm.

 

[bigdogeh]

Is the turbo seized? If it's not making any boost it will not make any power and fuel would be cut due to lack of boost pressure. TF

this is a good thing to check. and fairly easy to check also...

 

[noluck]

is it a trailer boat or moored

 

[baddogg]

Check this out

Engine Won't Reach Operating RPM. Check
1.Fuel condition. Type and Octane possibly old fuel

2. Propeller pitch or diameter, damaged blades

3. Restricted fuel pickup tube or anti siphon valve Fuel System Test

4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse

5. Marine growth on hull and outdrive

6. Wrong gear ratio in outdrive

7. Restricted carburetor air intake (clogged flame arrestor)

8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive

9. Poor cylinder compression

10. Carburetor defective, or wrong type
.
11. Fuel pump pressure and vacuum

12. Boat overloaded, improperly loaded, or improperly trimmed.

13. Engine Overheating

14. Engine timing and ignition system operation

15. Remote control cables and linkage for proper travel to open throttle plates fully.
__________________

I had a similar problem in my gas motor. It would not reach WOT ( Wide Open Throttle) turns out my exhaust manifolds and risers were restricted with corrosion.

 

[Battle Bay]

Had a couple with the waste gate seized open, the shaft sits right under the dog house lip and gets wet. With some gaskets and a little heat was able to get it working again

 

[Island Fish Lifter]

sounds like a turbo issue, however there should be lots of black smoke if that is the case, depending on how your AFC works. Whats on it for a pump? Timing may be an issue as well. Does it have a waste gate?